On outgoing calls, the Call Manager first searches the call routing table from top to bottom. If the Call Router cannot find a matching entry there, it uses the list of registered users:
| User | dials | correct call route | correct user | mapping, number in use | Destination line | |
|---|---|---|---|---|---|---|
| VoIP telephone | 11 | None | VoIP softphone | 11 | Internal | |
| VoIP telephone | 0 555 555 | 0# | 0241#: 0241 555 555 | ISDN | ||
| VoIP telephone | 0 0123 666 666 | 00# | 0#: 0123 666 666 | SIP provider |
- The Call Router cannot find a an entry that corresponds to '11' in the call routing table. Now it searches the list of registered users and finds the internal SIP user there.
For call routing, not just the users configured in the LANCOM, but all of the users that are actually registered on the Call Router are used. The SIP users can register themselves as long as they are not entered in the in the LANCOM. The entry for the internal VoIP domain on the LANCOM is sufficient for registration, assuming that local authentication is not required.
- The entry in the call routing table depicted above matches the number dialed. The call router removes the '0' outside-line access prefix, completes the area code for the local telephone network and completes the call to '0241 555 555' using the ISDN line.
The area code for the local telephone network is added on because calls via SIP providers usually require the area code to be dialed.
- The entry in the call routing table is suitable here. The call router removes the '0' prefix for access to the outside line and completes the call to '0123 555 555' via the SIP line. If the SIP line is not available, then the call is made over the ISDN line.